This invention relates to a refrigerant charging system which is for use in charging a refrigerant into a storage container. More particularly, this invention relates to a system which is of the type described and operable in a self-heat exchanging system.
A refrigerant, such as a fluorocarbon refrigerant, is commonly employed in an air conditioner of an automobile or a refrigerator.
A refrigeration system will operate more efficiently when the refrigerant is pure and relatively free of pollutants, such as oil, air and water. But, a used refrigerant becomes impure by pollutants.
Therefore, it is necessary to periodically remove and recharge the refrigerant within the refrigerant system.
Various refrigerant charging systems are already known. In the Miyata et al article, a citation is made to a refrigerant charging system of the type disclosed in Japanese Patent Prepublication (Kookai) No. 251767 of 1988.
In a manner which will later be described in connection with this invention, such a refrigerant charging system comprises a receiving unit which receives an object refrigerant to make a modified refrigerant in a liquid phase, through the use of an evaporator included in an external freezing or refrigeration circuit. The external freezing circuit is operated to cause evaporation of another refrigerant in the evaporator. The object refrigerant is produced from an original refrigerant which is employed in, for example, an air conditioning system. The modified refrigerant is dropped from the receiving unit into a storage container by gravitational force, to thereby charge the modified refrigerant to the storage container. However, the inevitable need to use an external freezing circuit causes a problem for modifying the object refrigerant.
In addition, the inner pressure of the storage container becomes high in response to an increase of the modified refrigerant in the storage container. As a result of the high pressure, it is assumed that the modified refrigerant does not charge to the storage container.